The present invention relates to valves used in patient support systems, and more particularly to valves used to regulate the flow of air used for inflating sacs in a low air loss patient support system.
Examples of low air loss patient support systems include those described in U.S. Pat. Nos. 4,638,519 to Hess; 4,686,722 to Swart; 4,745,647 to Goodwin; and 4,949,414 to Thomas etal., which are hereby incorporated herein by reference. U.S. Pat. Nos. 5,044,029 and 5,062,171 to Vrzalik disclose another type of low air loss patient support apparatus which includes an air controlled box interposed in the flow of air from a gas source to a plurality of gas manifolds that connect to the air bags. The air control box has individually adjustable valves for changing the amount of gas delivered to each of the gas manifolds.
The patient support systems of today demand increasingly sophisticated control valves. Moreover, a low air loss patient support requires maintenance by both technical personnel and hospital personnel. The cost of providing such maintenance is directly proportional to the time required to perform such maintenance. Time spent repairing a flow control valve while it remains in the patient support, as well as time spent removing and replacing the valve so that the removed valve can be repaired at a remote location, contributes to the maintenance cost (including the cost of non-use of the patient support during the repair) of the patient support. Thus, the sophisticated patient support systems of today require increasingly reliable and trouble-free flow control valves if the system is to be cost effective in an environment that is becoming more sensitive to ever increasing hospital and health care costs.